Process of decomposing refractory silicates.



WILLIAM T. GIBBS. OF BUCKlNGl-IAM, (JANAILX.

PROCESS OF DECOMPOSING-REFRACTORY SILICATES.

SPECIFICATION forming part of Letters Patent No. 772,657, dated October 18. 1904.

Serial No. 209,113. (No specimens.)

Application filed Kay 21. 1904.

To all whom, it may concern:

Be itknown that LWVILLIAM T. Gums, a subect of the King of Great Britain and Canada, residing at Buckingham, county of Ottawa, Province of Quebec, Canada, have invented certain newand useful Improvements iuldethods of Decomposing Refractory Silicates,described in the following specification.

This invention relates to a new method of decomposing or breaking up refractory silicates-such, for instance, as the feldspar-s, Y

i 1 z i ing them with a solution of hydrofiuosilicic acid, so as to remove the basesfrom their com bination with the silica by combining them with the acid. The quantity of hydrofluosilicic acid is p eferably in excess of the amount required to embine with the bases, so as to assure complete decomposition of the silicates and to avoid an unnecessarily slow reaction toward the end of the process; but this is not essential to the invention, broadlyc msidered. After the decomposition the solution and residue may be treated as desired for the recovery' of the valuable constituents. and the siiico-fluorids of the bases formed by their combination with the hydrofluosilicic acid are preferably treated so as to recover the hydrofluosilicic acid to be again used used in the process.

The preferred manner of carrying out my complete process is as follows, described as applied in connection with feldspar: The feldspar is ground, preferably in a pebble-mill, so as to be reduced to a line powder, preferably to the finest dust possible, and in practice air separation may well be used in connection with fine grinding.

is then put in a suitable tank and digested with a solution of hydrofluosilicic acid, which should be as strong as practicable. It is impractica'ole. however, to obtain a solution of more than thirty-five to forty per cent. acid, and a The pulverized feldspar solution of this strength works very satisfactorily. Acid of much lowcr strength may be used, however; but the action would necessarily be slower and less economical as compared with a stronger acid. As stated above, the amount of hydrolinosilicic acid originally introduced is preferably in excess of the amount required to combine with the bases so as to assure complete decomposition of thesilicates with a reasonably rapid re ction th rough out the process. The same 1 .ult of having the amount of the hydroiluosilicic acid in excess of the amount required to combine with the bases may obviously be secured by adding hydroliuosilicic acid during the process. After the feldspar is completely decomposed the solution contains the alumina as silico-t'luorid of aluminium, and the residue consists of the silica prexiously combined in the spar and silico-iluorid of potassium. The solution is then prc ferablyscparated from the residue by filtration and may then he treated by evaporation to obtain the salt of alumina in a solid condition, and from this salt the sulfate or other compound may be prepared by any known method. If treated with sulfuric acid, sulfate of alumina is formed, and hydroli'uosilicic acid is volatilized and may be recovered by condensation. The residue may be treated in any known manner for the recovery of the potash contained therein and the separation of silica as such. This maybe accomplished by treating the residue with sulfuric acid, in which case sulfate of potassium is obtained in solution, the silica is left as an insoluble residue. and the hydrofluosilicic acid J1: densation. v

It will be understood that the present invention relates only to the decomposition of the refractory silicates and the recovery of the hydrofluosilicic acid for reuse and that the products'of the decomposition may be treated j in any suitable manner, according to the final products desired. T he treatment of the produsts of decomposition stated above are given or 1y as examples of methods that may be used, and the process forming the present invention is not limited thereto.

volatilized and may be recovered by conacid.

The method of decomposing: refractory areas of the amount required to combine siiicatcs, which consists in reducing the cilic-ati-s to n inch-divided condition and troutingr thcin with a soiution containing hydroflno. iiicic acid, the hydroflnosiiicie acid being in excess of the amountrcquired to combine with the baaes of the silicate.

3. The, method of dccomposing rcfractor siiicates, which consists in reducing the siiicater: to a finely-divided condition, removing the hases from their combination with the &

Siiica hyconihining them with ilytiIUfiUOSiiiCiC acid, and subsequently treating the'silico-fluoriis-of the bases to recover the hydrofluoniiicic acid.

4. The method of decomposing refractory silicates. which consists in reducing the sili- (ates to a finch-divided condition, treating them with a solution containing hydrofluosihc-ic acid. the hydrofluoslhcic acid being in with the bases of the silicate, and subsequently treating the siiico-fluoriiis of'the buses to recovcz the fwdroiiuosilicic acid.

in tcstimcny whereof I havehcrennt-o set my ham! in the presence of two subscribing witnesses.

. \VILLIAM T. GIBBS. Witnesses:

FRED. J; HAMBLY, EDGAR Roy. 

